An apparatus for moving a wheelchair on a flight of steps has a support adapted to engage underneath the wheelchair in an upright condition of same with the chair pivotal on the support between erect and inclined positions. Two or more endless tracks on the support carry same and the wheelchair thereon so that the tracks allow the wheelchair to move over uneven terrain and up and down stairs. A latch is displaceable on the support between a holding position securing the wheelchair in the inclined position and a freeing position permitting the wheelchair to move freely between its positions. The latch is provided with a pedal to displace it into the freeing position. The support inclines a frame element pivotal on the support about a horizontal axis transverse to the tracks and a device for securing the frame element to the wheelchair on the support.
As disclosed in our copending patent application Ser. No. (511,791 filed July 7, 1983) a safety device connected to the latch is responsive to the inclination of the tracks relative to the horizontal for blocking the latch from moving into the freeing position when the tracks are inclined at more than a predetermined angle to the horizontal. Thus the wheelchair cannot be released from the support when same is moving on an incline.
Wheelchairs differ considerably in size, so it is necessary to be able to adjust the position of the securing means that connect the frame element to an element of the chair. Thus it is standard to provide two independent clips that are movable horizontally and vertically on a frame element of the support. For adjustment it is necessary to reposition both of the clips and secure them in place on the support, then connect them to the frame of the wheelchair. This is an onerous job that is often not carried out carefully so the clips do not securely grip the wheelchair frame.
In addition these systems require both of the clips to be adjusted horizontally when a narrower or wider chair is being engaged since the chair should be centered in the stair climber. Unfortunately this extra work is frequently not done, that is only one clip is adjusted. The result is offcenter positioning of the chair which can make the climber excessively tippy and potentially quite dangerous. Even a conscientious operator often misjudges the precise centered position of the chair being carried and maladjusts the system.